Stage 0 includes: Tis, N0, M0. Tis: Carcinoma in situ. Squamous cell carcinoma in situ (SCIS). Adenocarcinoma in situ (AIS): adenocarcinoma with pure lepidic pattern, 3 cm or less in greatest dimension. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th ed.) [from
NCI]